Process or method of making waterproof paper tubes



Feb. 2 1926.

J. H CARMICHAEL PROCESS OR METHOD OF MAKING WATERPROOF PAPER TUBES Filed Feb. 18. 1 925 Invenior Jawwslrf. 0a,?

Patented Feb. 2, 1926.

UNITED STATES PATENT OFFICE.

JAMES H. CARMICHAEL, 0F LOWELL, MASSACHUSETTS, ASSIGNOR TO U. S. CARTRIDGE COMPANY, OF LOWELL, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

PROCESS OR METHOD OF MAKING WATERPROOF PAPER TUBES.

Application filed February To all whom it may concern:

Be it known that'I, JAMEs H. CARMIoH- AEL, a citizen of the United States, and a resident of Lowell, in the county of Middlesex and State of Massachusetts, have invented an Improvement in Processes or Methods of Making Waterproof Paper Tubes, of which the following description, in connection with the accompanying drawings, is a specification, like characters on the drawings representing like parts.

This invention consists in improvements in the manufacture of waterproof or water resisting paper tubes and more particularly those which are employed in the manufacture' of shot-shells. It is desirable that such shells be produced from tubes which are hard and tough and of smooth exterior finish, exhibiting strong resistance to moisture and able to hold a crimp.

In the manufacture of paper tubes for this purpose it is customary to utilize a. sheet of paper which is usually uncalendered.

Paste or other adhesive is applied to its sur-- faces and the sheet is then rolled up on a mandrel to form a tubular body with a. plurality of superposed coils of paper bound together by the paste. The tubular body is then dried to produce a hard, firm paper tube and afterwards subjected to the action of a sizing machine in which it is passed through rotary dies by which it is'polished and brought to an exact size.

It is desirable and necessary that the surface of these tubes when employed'for shotshells shall be waterproof or water resisting, and this invention relates more particularlyto the steps by which that result is secured. The present method of making waterproof or moisture resisting tubes is to apply a gelatinizing or polymerizable oil after the tube has been formed, but as the paper has been impregnated with paste there is more or less dlfiiculty of having the oil penetrate the hardened paste. a

In my improved process a coating of polymerizable oil is applied to one side of a sheet of paper from which the tube is to be rolled and prior to the rolling thereof. This permits a tube to be produced which, when finished, presents an oil coated exterior with the oil coating smoothly and uniformly applied throughout. This exterior coating may be gelatmized-elther m the sheet before rolling or after the completion 18, 1925. Serial No. 9,957.

of the tube or after the sizing thereof, or in the preferred method it is gelatinized as an incident to the drying of the tube, so thattaken in connection with the accompanying illustration of one specific embodiment thereof, While its scope will be more particularly pointed out in the appended claims.

In the drawings,

Fig. 1 represents the sheet of paper from which the tube is to be formed and showing the portion coated with oil;

Fig. 2 is a side elevation on a slightly larger Scale showing the tube when rolled up; an

Fig. 3 is a cross-sectional elevation showing, with a greatly exaggerated thickness, the convolutions of the paper constituting the tube.

Referring to the drawings, the invention may be carried out by utilizing a sheet of paper such as 'the sheet 5 shown in Fig. I. This'is preferably uncalendered paper, relatively tough and of sufiicient dimensions to roll up into a tube of the required diameter with a number of convolutions or thicknesses. As it is customary to impart a distinctive color to the finished tube, the outer (right-hand in Fig. 1) edge 7 of the sheet may be colored on one side with a band 9 of color, which, when the tube is completed, will be more than sufiicient to envelop the entire outer circumference of the tube. It is not essential, however, that the paper be colored as described.

In carrying out my improved process, the outer edge of the paper sheet on the slde which is to constitute the outside of the tube is also given a coating 11 of polymerizable oil, such coating being superposed on theband of color in cases where the paper is colored. This coatin may be of any desired width or extent, nt I prefer to confine it to such a portion of the paper sheet where.

hesive in the formation of the tube. To that end, the oil coating preferably terminates just short of the marginal edge and extends substantially parallel to the edge for a width approximating but not greater than the circumference of the tube to be formed. -When the tube is finally formed, therefore, the lapping outer edge 7 of the sheet falls even with or just short of the inner edge 13 of the oil coating on the underlying convolution of the sheet, so that the action of the adhesive in sealing the overlapping outer edge cannot be aifected by the presence of the oil. There may also be left a narrow margin of the uncalendered paper between the outer edge 7 of the sheet and the outer edge 15 of the oil coating, so that the edge receives the full action of the adhesive unimpaired by the presence of oil at the edge, although this is not essential.

Various kinds of polymerizable oils may be utilized, but I have found that a heavy ordinary linseed oil gives excellent results. This may be applied in any desired manner, either by hand or mechanically, and may be done simultaneously with the rolling operation. Preferably the oil is applied just before the rollingoperation so that the drying, hardening and gelatinizing can take place at the same time in one operation, but gelatinizing can take place at any time and, if desired, the oil can be applied and gelatinized before rolling with good results.

In applying the oil mechanically to the paper, the latter may be conveniently fed between the rolls, one of which is covered with rubber, leather or like material, a film of oil of the desired width being applied to the latter surface as the rolls are revolved nd the paper sheet fed between the same.

In the manufacture of the tubes the sheets, prepared as described, are then coated with adhesive and are rolled up on a mandrel of suitable size to produce a tube of superposed coils of paper (see Fig. 3) bound together and consolidated by the intervening film of aste. p Formation of the tubes may be done by hand, but they are ordinarily formed in a machine, each sheet being picked up fiat and fed ween rolls that are subjected to a stream of fluid adhesive paste, the sheet being then engaged by a mandrel and rolled up into tubular form. The moist tubes thus formed are completed by being dried to set and harden the paste. The tubes are usually first partly dried in the air and then subjectedto an oven heat to polymerize the oil.

The tube thus produced presents an outside coating or convolution of' pa er which is oil coated for its entire circum erence or approximately so with a uniformly applied coating of polymerizable oiL This exterior coatingmay be gelatinized to produce a water resisting surface either on the sheet before rolling, or after the drying and completion' of the tube and before the sizing operation, or after the subsequent sizing thereof. In my preferred process, however, I submit the oil to a gelatinizing action before the sizing operation of the tube by subjecting it to an appropriate heat in a drying oven, the heat of which-is preferably maintained somewhat above 210 or 2159 F. The drying operation thus acts simultaneously to dry out the paste, harden the tube and gelatinlze the oil.

The tubes, after being thus completed with their gelatinized coating of linseed oil, are usually subjected to a. sizing operation in the course of which they are drawn through rotatable dies which serve to bring the tubes to a more uniform and exact size or dimension.

The gelatinizing of the linseed oil by heat might take place if desired after the sizing of the tubes, but I prefer to carry it out at the same time the tubes are dried and before the completion of the latter, not only because it saves an extra step in the process, but because the sizing of the tubes after the gelatinization of the oil appears to give more uniform and better water resisting results than where the tubes are sized before the oil is gelatinized.

-Tubes made from paper treated by the described process have an advantage in that the oil penetrating into the fibre makes a waterproof surface that extends into the tube nearly the thickness of the outside lap of the tube adding greatly to the strength of the tube and preventing abrasions and injuries from rough usage.

VVhile' I have herein described in detail one mode of carrying out my improved process, the same may be varied within wide limits without departing from the spirit of the invention.

Claims:

1. The process of making water resisting paper tubes which consists in applying a coating of polymerizable oil to one side of a sheet of paper, such coating terminating short of the marginal edge and extending substantially parallel to the edge for a width slightly less than the circumference of the tube to be formed, applying adhesive to the sheet, rolling it up to form a tube with the oil coated portion on the outside, drying the paste, and simultaneously gelatinizing the oil and subjecting the tube to a sizing operation.

2. The process of making water resisting paper tubes which consists in applying a coating of polymerizable oil to one side of a sheet pfpaper adjacent the marginal edge leaving an unoiled margin, said coating extending parallel to the edge for a width approximating the circumference of the tube to be formed, applying adhesive to the sheet,

rolling it up to form a tube with the oil coated portion on the outside, drying the pgste, and gelatinizing the polymerlzable o1 3. The process of making water resisting paper tubes for shot shells and the like which consists in feeding the sheets through paper rolls and applying a coating of polymerizable oil to a portion of the sheet and a coating of adhesive material to the remainder of the sheet during the feeding operation, said oil coated portion terminating short one marginal ed o of the sheet and heingof a width slight y less than the circumference of the tubev to be formed, rolling it up to form a tube with the oil coated portion on the outside, drying the adhesive material and sizing the tube to form a substantially perfect waterproof exterior.

In testimony whereof, I have signed my name to this specification.

JAMES H. CARMIGHAEL. 

